Some Basic ConceptsFor

Managing Land

Dr. Karl Wood, DirectorWater Resources Research Institute

Stucky HallNew Mexico State University

Suppose you have just acquired some land!

• What is the climate?• What is the topography?• What plants and animals are present?• What is the soil condition?• What are the goals for land?• What is it capable of growing?• Are the goals ecologically, socially, and

economically feasible?

Some questions need to be answered:

To answer these questions,

some scientific understanding is needed.

Sunshine Water Minerals Nutrients

Primary ProducersPlants 6000 cal/m2/yr Plants

Primary ConsumersMice 600 cal Sheep

Secondary ConsumersSnake 60 cal Wolf

Tertiary Consumer

Eagle 6 cal

Dec

omp

oser

s

heat

heat

heat

heat

Trophic Energy PyramidExample

Based on Second Law of Thermodynamics

Exploitation Sustainable Protection

Use

Land Goal?

The extremes result in attitudes of supremacy

From: Thompson, P.B. 1995. The Spirit of the Soil - Agriculture and Environmental Ethics. Routledge Publ. New York, New York

Concept of the Sere

Bare Rock

Lichens

Soil depth and richness

Climate

Time

Example developed in North America by H.C. Cowles and F.E. Clements about 100 years ago

Exampleof a

lichen&

associatedanimals

Concept of the Sere

Bare Rock

Lichens

Mosses

Soil depth and richness

Climate

Time

Example of a moss

&associated

animals

Concept of the Sere

Bare Rock

Lichens

Mosses

Soil depth and richness

Climate Annual grasses and forbs

Time

Example of

annual grasses and

forbs&

associatedanimals

Concept of the Sere

Bare Rock

Lichens

Mosses

Soil depth and richness

Climate Annual grasses and forbs

Perennial grasses and forbs

Time

Examples of perennial grasses

and forbs&

associatedanimals

Concept of the Sere

Bare Rock

Lichens

Mosses

Soil depth and richness

Climate Annual grasses and forbs

Perennial grasses and forbs

Shrubs

Time

Example of

shrubs&

associatedanimals

Concept of the Sere

Bare Rock

Lichens

Mosses

Soil depth and richness

ClimateAnnual grasses and forbs

Perennial grasses and forbs

Shrubs

Deciduous trees

Time

Exampleof

deciduous trees

& associated

animals

Concept of the Sere

Bare Rock

Lichens

Mosses

Soil depth and richness

ClimateAnnual grasses and forbs

Perennial grasses and forbs

Shrubs

Deciduous trees

Time

Conifers

Example of

conifersgrowingthrough

deciduousforest

Example of

conifers&

associatedanimals

Concept of the Sere

Bare Rock

LichensMosses

Soil depth and richness

ClimateAnnual grasses and forbs

Perennial grasses and forbsShrubs

Deciduous trees

Conifers Climax

Time

Each levelIs called a“seral stage”

Concept of the Sere

Bare Rock

LichensMosses

Soil depth and richness

ClimateAnnual grasses and forbs

Perennial grasses and forbsShrubs

Deciduous trees

Conifers Climax

Time

Primary

Successi

on

Retrog

ressi

on

Seco

ndar

y

succ

essio

n

• The kinds of animals are different in each seral stage.

• The climax seral stage usually does not represent the greatest species diversity of plants and animals.

• Subclimax seral stages may be maintained by continuous or discontinuous perturbations such as fire, grazing, hurricanes, etc.

• Movement towards climax is called succession

• Movement away from climax is called retrogression (e.g. Desertification)

• Multiple equilibrium communities and complex successional pathways may be possible within a sere.

General Comments On Ecosystem Succession

To manage an ecosystem, managers need to know:

1. What is the potential or climax seral stage of the area?

2. What is the present seral stage of the area?

• Is it all the same or are there different seral stages in different parts of the area?

4. Can the preferred seral stage be achieved with the present technology, time, legal, political, and economic constraints?

3. Are there several acceptable seral stages and a preferred seral stage of the area and/or its parts?

Concept of the Sere

Bare Rock

LichensMosses

Soil depth and richness

ClimateAnnuals

Time

Mostchoicesare here!

ConifersDeciduous trees

ShrubsPerennial grasses and forbs

Concept of the Sere

Bare Rock

LichensMosses

Soil depth and richness

ClimateAnnuals

Time

What seral stageHas the most

Plant and animalDiversity? Conifers

Deciduous trees ShrubsPerennial grasses and forbs

Diversity(number of plant

& animalSpecies)

Bare Rock

ClimaxSeral Stage

Concept of the Sere

Bare Rock

LichensMosses

Soil depth and richness

ClimateAnnuals

Time

Can the Seral stageEver be above Climax? Conifers

Deciduous trees ShrubsPerennial grasses and forbs

Concept of the Sere

Bare Rock

LichensMosses

Soil depth and richness

ClimateAnnuals

Time

Yes! Deciduous trees

Artifical inputs of waterand nutrients (Fertilizer)

Example:

Perennial grasses and forbs (Desert grasslands)

(Pecan orchard)

Must have adequate soil depth!

Concept of the Sere

Bare Rock

Lichens

Mosses

Soil depth and richness

Climate Annual grasses and forbs

Perennial grasses and forbs

Time

When retrogression occurs,increased erosion rates can

be expected. Example:

NativeGreat Plains

Converted to cropland(corn, soybeans, wheat, cotton)

Nature abhors a void

Nature abhors topographical prominence

Nature abhors a crowd

Natural changes are often dynamic and catastrophic with unpleasant consequences for humans

Changes in nature due to human activities may be dynamic and catastrophic, or static, controlled, predictable, and beneficial to

humans, animals, and the land where they live.

Human influence is most probable for avoiding catastrophes and assuring ecological, social, and

economic stability.

Conclusions

Healthy Land = preferred seral state is attained

Sustainability = preferred seral stage is maintained against the processes of succession and

retrogression, including invasions, especially by exotics

Conclusions

God bless America!

And PistolPete!

Thank you!

Thank you!